Although it has been a common practice for many years to provide straw chopper attachments at the rear of combines for disintegrating and spreading larger crop residue, such as leaves, stems and stalk portions separated from the grain during threshing operations within the combine, little attention has been paid to the fine, very lightweight chaff particles such as hulls and husks that surround the seed and are also separated by the combine during its threshing process. Because of the very light nature of such chaff particles, they are inherently difficult to handle, and yet they need to be spread evenly on the field as they are discharged from the combine rather than be dumped in irregular, concentrated clumps.
Accordingly, one important object of the present invention is to provide a spreading attachment for the chaff discharge outlet of a combine which is capable of receiving chaff as it issues from the conventional discharge outlet of a combine and propelling it away from the immediate vicinity of the harvester to scatter and diffuse the chaff relatively evenly on the field as the harvester continues to advance.
In carrying out this object, the present invention contemplates the attachment of an auxiliary air source to the combine which produces a rapidly, yet smoothly, flowing carpet of air in a transversely disposed discharge trough so the chaff particles are directed onto the air stream as they exit the combine and are quickly projected laterally outwardly of the harvester where they fall to the ground in a diffused and scattered condition. In preferred form, the invention contemplates a trough that extends across the rear of the combine and which receives an airflow near the center of the trough which is split into two oppositely moving, left and right air streams that are effective in carrying the chaff to outboard locations. Chaff emanating from the discharge outlet of the combine falls down into the trough near the central point and is immediately entrained by the oppositely moving air streams for delivery to the outboard locations. An upright baffle at the aft end of the trough helps deflect errant chaff particles down into the oppositely moving streams.